Conventional tank-mounted automotive fuel pumps typically have a rotary-pumping element, such as an impeller with a plurality of grooves encased within a pump housing. Rotation of the impeller draws fuel into a pumping chamber within the pump housing. The rotary pumping action of the vanes and the vane grooves of the impeller causes the fuel to exit the housing at high-pressure. Regenerative turbine fuel pumps are commonly used to pump fuel in automotive engines because they have a more constant discharge pressure than, for example, positive displacement pumps. In addition, regenerative turbine pumps typically cost less and generate less audible noise during operation.
As fuel pumps get smaller and smaller to achieve higher pressures, the housing that contains the pumps have tighter tolerances. To achieve these tolerances, the current housings are made of anodized aluminum. Anodized aluminum works well in pure gasoline systems, but has a tendency to corrode when gasoline is mixed with flex fuels or other aggressive fuels such as methanol/gasoline or ethanol/gasoline mixtures.
Various solutions have been attempted to replace anodized aluminum in fuel pump housing. One solution is to coat the anodized aluminum, however this is very costly. Another possible solution uses a thermoplastic or thermosetting material to replace the anodized aluminum housing designs. However, conventional housing using thermoplastic or thermosetting materials typically experience one of two problems. First, thermoplastic or thermosetting housings having narrow seal surfaces between the cover and the housing cannot be used in high-pressure applications (greater than 100 kpa) because their narrow seal surfaces tend to creep. Second, where the seal surface width is increased to combat creep and allow the housings to be used in higher pressure (300-500 kpa) applications, the friction generated between the housing and the impeller increases.